NAMM 2020 seems to be already producing some interesting headphone-related announcements, with two from HEDD and Austrian Audio catching our attention in particular because of their focus on drivers.

HEDDPhones

Back in July 2019, we shared the announcement that HEDD was developing as headphone using a driver based on their AMT tweeter. The Air Motion Transformer is frequently misnamed as a “ribbon tweeter” and is misunderstood to be similar to the planar drivers found in headphones from manufacturers such as Audeze. Both planar drivers and AMTs are built using thin membranes and without the voice coil of conventional electrodynamic drivers. Planar drivers are pistonic, actually, they are very pistonic, that’s one of the advantages. To find out more about why a planar driver offers some interesting ways to get around some of the issues common to conventional electrodynamic drivers read this piece on how Audeze drivers work.

AMTs are not pistonic and the mechanical advantage of approximately 4:1 offered by the AMT is responsible for some of the perceived benefits of improved transient response. The geometry of the driver used as a tweeter in HEDD monitors has been redesigned to fulfil the design brief of a full range driver suitable for headphone use and the resulting new driver is finally available for us to hear.  

They have announced the product will be shipping in January 2020 and can confirm the details of the final design. We’ve been waiting to see these in the flesh and we’ll finally get a chance at this week’s NAMM show.

Technical Data

• Open over-ear headphone

• Full-range Air Motion Transformer with VVT® Technology

• Up to 3 times the diaphragm size compared to conventional drivers

• Efficiency: 87 dB SPL for 1 mW

• Impedance: 42 Ω

• Weight: 718 g

• Mini-XLR Connector, high-quality 6,3mm single-ended 2 m cable included • Custom artificial leather earpads

• Hand-built in Berlin, Germany

HEDD says…

HEDD introduces the first full-range Air Motion Transformer headphones. Designed by loudspeaker-veteran Klaus Heinz (Founder of ADAM & HEDD) and build from scratch in Berlin Germany, the HEDD Air Motion Transformer is a unique transducer that HEDD believes delivers a more musical and true-to-the-source audio performance. By squeezing the air out of a multiple Kapton® folds, it allows to move air significantly faster than any traditional dynamic, electrostatic or planar magnetic driver, resulting in a more accurate transient response and stereo imaging. This makes the HEDDphone® suitable for both, music creation and high-end listening. details of. The final design.

Austrian Audio Hi-X Headphones

The other announcement which caught our attention is the new Hi-X headphones from Austrian Audio.

Austrian Audio was formed with approximately 22 former AKG personnel from management and the core engineering disciplines including Acoustics, Electronics, Test & Measurement, Mechanical Design, RF/Wireless, and Software/Firmware. After the closure of their legacy home in Vienna, the core team set out to create something new, challenging, and respectful of the best of their heritage, bringing along 335 years of cumulative engineering experience.

We saw their first product at AES 2019 - the OC818, which is a multi-pattern dual-output condenser microphone equipped with what is claimed to be a world-first - optional wireless control.

Back to the Austrian Audio Hi-X headphones, while they use conventional electrodynamic drivers, this design highlights the importance of driver diameter and excursion. An interesting area from a design point of view and just as relevant to headphone design as it is to speaker design, though of course, the application is different, a large speaker displaces more air than a small one and as a result doesn’t have to move as far or as fast. However, the larger a driver is the thicker it has to be built to maintain rigidity, if not stiff enough a driver flexes and breaks up resulting in distortion. Higher excursion allows a smaller, stiffer, lighter driver to move the same amount of air as a large one but without the issues of stiffness and weight.

Austrian Audio Say:

The on-ear, supra-aural Hi-X50s are specifically designed for those requiring a portable and compact option, whereas the Hi-X55 circum-aurals provide over-the-ear comfort. Both feature Austrian Audio’s exclusive 44mm Hi-X driver.

“Our engineers have designed larger drivers in the past, but our science, measurements and listening tests have shown that 44mm is the best size for this design,” explained Philipp Schuster, Product Manager. “It ensures optimal performance in the Hi-X by moving a lot of air, and eliminates ‘wobbling’ of the diaphragm. It’s all about controlled sound – 44mm is optimal for the professional Hi-X series. “

Tech Specs

• Frequency range: 5 Hz - 28 kHz

• Sensitivity: 118dBspl/V

• THD (@ 1kHz): < 0.1%

• Impedance: 25 Ω

• Input Power: 150 mW

• Cable (detachable): 3m

• Connector: 3.5mm (1/8”)

• Adapter (included): 3.5mm to 6.3mm (1/8” to 1/4")

• Dimensions: 300 x 170 x 85 mm

• Weight (without cable): 305g